Overvoltage protection circuit, and power source, power supply system and electronic apparatus using the overvoltage protection circuit

Inactive Publication Date: 2005-04-14
HITACHI LTD +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

[0024] Constructing a power supply system of a redundant parallel configuration using the power sources mentioned above makes it possible to improve the reliability of the power supply system. In

Problems solved by technology

Depending on the particular failure mode of the power source, however, the expected improvement in reliability may not be obtainable.
In the overvoltage failure mode, however, it may not be possible for the reliability of the power supply system to be improved using the conventional technology.
Therefore, the power supply system lacks the required output current capacity and does not function properly or is dea

Method used

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  • Overvoltage protection circuit, and power source, power supply system and electronic apparatus using the overvoltage protection circuit
  • Overvoltage protection circuit, and power source, power supply system and electronic apparatus using the overvoltage protection circuit
  • Overvoltage protection circuit, and power source, power supply system and electronic apparatus using the overvoltage protection circuit

Examples

Experimental program
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Example

[0037]FIG. 2 shows a first embodiment of the present invention. In FIG. 2, similarly to the conventional technology, output terminals of power sources 400 and 500 are connected to an output terminal 600 of a power supply system (hereinafter, referred to simply as the power system) via series-connected OR diodes 403 and 503 to realize the power system of a redundant parallel configuration. The first embodiment is characterized in that independency-discrimination circuits 417 and 517 and the connection circuits 418 and 518 functioning as AND circuits in this example, are provided in addition to the circuits of the conventional technology. In the first embodiment, in addition to overvoltage detection circuits 414 and 514, the independency-discrimination circuits 417 and 517 and the connection circuits 418 and 518 form an overvoltage protection circuit.

[0038] Internal operation of the power source 400 is described below. An input of the independency-discrimination circuit 417 is connec...

Example

[0040]FIG. 3 shows a second embodiment of the present invention, wherein a part of a power system, namely, a power source 700 is mainly shown. An output terminal 702 of the power source is connected to an output terminal 799 of the power system via an OR diode 703. A similar power circuit is connected to the output terminal 799 of the power system and hence realizes parallel operation. FIG. 3 differs from FIG. 2 in that an input of a independency-discrimination circuit 717 is taken from an input end of a current comparison circuit 711. The independency-discrimination circuit 717 monitors the voltage developed across a resistor 709 connected to the input of the current comparison circuit 711, and discriminates whether an output voltage of the local power source is higher or lower than that of other power source not shown. Only the power source where an overvoltage has occurred can be selectively deactivated. More specifically, this is possible by taking a logical product between the ...

Example

[0042]FIG. 4 shows a third embodiment of the present invention, wherein a part of a power system, namely, a power source 800 is mainly shown. In FIG. 4, an input of a independency-discrimination circuit 817 is connected to a current comparison circuit 811 similarly to FIG. 2, whereas an output is connected to an addition circuit 819 which, as a connection circuit, adds a voltage to that of the reference voltage source 815 provided for an overvoltage detection circuit 814. The present embodiment is adapted such that when the independency-discrimination circuit 817 discriminates that an output voltage of the local power source is lower than that of the other (remote) power source, a voltage value for detecting an overvoltage is increased via the addition circuit in order for operation of the overvoltage detection circuit to change. Thus, an overvoltage detection circuit of the power source where an overvoltage failure has occurred operates first, hence preventing the other (normal) po...

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Abstract

In a redundant configuration with multiple power sources connected in parallel to enhance reliability, a power source in which an overvoltage failure occurred has been difficult to identify and unable to be deactivated, which has impeded the improvement of reliability. However, it has become possible to deactivate selectively only the power source in which an overvoltage failure has occurred, by providing a independency-discrimination circuit that identifies the occurrence of the overvoltage failure by use of the state of a parallel operation control circuit, and connecting the independency-discrimination circuit, an overvoltage detection circuit, and a connection circuit.

Description

CLAIM OF PRIORITY [0001] The present application claims priority from the Japanese patent application JP2003-314898 filed on Sep. 8, 2003, the content of which is hereby incorporated by reference into this application. BACKGROUND OF THE INVENTION [0002] The present invention relates to an overvoltage protection circuit of a redundant parallel configuration, and to a power source, power supply system, and electronic apparatus using the overvoltage protection circuit. [0003] A power source may be designed to take a redundant parallel configuration for improved reliability. When connecting multiple power sources in parallel to construct a power supply system of a parallel configuration in which the power sources are to be operated in parallel, more power sources than the N number of units actually required may be connected in parallel and operated in parallel (i.e., the power supply system may be designed into a redundant parallel configuration). Accordingly, even in the event of a pow...

Claims

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Application Information

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IPC IPC(8): H02H3/20G05F1/10H01G2/12H02H7/00H02M3/00
CPCH02H3/207H02M1/32H02J1/10
Inventor YAMAMURA, HIDEHOMARU, NAOKITOMIOKA, SATOSHIUEGURI, MOTOHARU
Owner HITACHI LTD
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